Dishwashing apparatus



p 6, 1961 o. L. LONG ET A]. 3,001,227

DISHWASHING APPARATUS Filed July 16. 1959 INVENTORS OLAN L LONG HAL H1 DRONBERGER FIG. BY W W Unitid States tent Another ob'ect of the invention is to provide a simple, inexpensive mechanism of the type set forth that is effective to balance the force due to the weight of the lid and which aries non-linearly throughout the range of movement of the lid.

A further object of the invention is to provide an improved counterbalance utilizing a conventional spring, whose bias varies linearly, for opposing the gravitational forces in a hinged lid of the class set forth, which forces vary non-linearly as the lid is moved to various positions.

In practising the invention, asapplied to a hinged dishwasher lid movable from a closed horizontal position to a generally vertical open position, an arm movable with the lid angularly about the hinge is provided. A tension rod is pivoted at one end to the arm and the lower end of the rod passes through a helical compres- Sign spring and bears against the free end thereof. The

other or fixed end of the spring abuts against a stationary portion of the dishwasher casing structure. During movement of the lid between its horizontal closed position and its generally vertical position, the moment due to gravity about the hinge is non-linear while the change in bias of the spring is linear. Compensation for this condition isprovided by a fixed bearing'plate or fulcrum which engages an intermediate portion of the tension rod and effects a change in the anguar relation between the rodjand the arm when the lid isabout half open. The spring whose bias has been greatly reduced atthis point isptherefore, assisted in balancing the lid between this half-open position and the vertical open position thereof. It will be understood, that-,- between the closed horizontal position of the lid and said halfopen position thereof, the compressed spring has sulficient biasing force to adequately counterbalance the lid.

The foregiiiiig and other objects are effected by the invention as will be apparent from the following description "and claims talfn in connection with the ac- 'cdnipanying damage," fdr'rhifi'g a part of'this application, in which:

FIG. 1 is a perspective illustration of a dishwasher lid counterbalanced in accordance with the invention;

FIG. 2 is a section taken along the line H-II of FIG. 1;

FIGS. 3 and 4 are views similar to FIG. 2, with the apparatus in different positions; and

FIG. 5 is an enlarged section taken along the line V-V of FIG. 4.

Referring to FIG. 1, the invention is shown applied to a movable lid 10 of a top opening dishwasher, the casing of which is shown in part at 11. Arranged within the casing is a conventional open top tub structure 12 (see FIG. 2) having an upstanding soft gasket 13 arranged peripherally on the open top thereof. The lid 10 may include an inner pan structure 14 which bears on the gasket 13 in the closed position of the lid as is understood. The lid 10 is carried by a pair of binge stuctures 15 of similar construction and each including ice 7 2 a fixed portion 16 and a swinging leaf 17 fixed to the lid in any suitable manner and pivoted by means of a pin 18 to the fixed portion 16.

In accordance with this invention, an arm 19 movable with the lid 10 angularly about the pin 18 is provided and this arm 19 is preferably integral with the hinge leaf 17. This arm 19 is a part of the counterbalancing mechanism associated with each of the hinge structures 15. Each mechanism further includes a tension rod 21 pivoted at its upper end, as shown at 22, to the end of the arm 19 and having a flange 23 formed on its lower end for seating the free end of a helical compression spring 24 of conventional construction. The upper end of the spring 24 bears against the fixed casing structure 11 and is prevented from sliding laterally thereon by a finger 25 extending downwardly from the casing adjacent the periphery of an opening 26 formed therein (see FIG. 5). The opening 26 in the casing and a registering opening 27 in the fixed portion 16 of the hinge receive the rod 21 which extends downwardly within the casing 11, as shown. For purposes to be described hereinafter, the intermediate portion of the rod 21 is bent as shown at 28 and one side of the rod 21bears against a fixed bearing plate or fulcrum 29 preferably carried by the fixed portion 16 of the hinge. The bearing plate 29 and the hinge 15 may be secured to the casing by suitable fastening devices 30 (FIG. 5).

g I The hinge structure 15 may be at least partially enclosed by a cover 31 extending transversely across the rear margin of the casing 11. Also, actuation of the lid between its horizontal closed position and its open positions may be effected by a handle 32 at the front marthe lid 10 about the pivot 18 vary non-linearly as the lid 10 is moved between its horizontal closed position (FIG. 2) audits generally vertical, full open position of FIG.. 4. As the lid 10 is moved in its opening direction, said moments of force would reduce in accordance with thecosine'of the angle of the'lid above the horizontal. This, of course, is non-linear; the moments re -ducing at a relatively slow rate during the early stages of the movement and; during a later stage beyond the half open or 45 position, of FIG. '3, the rate of reduction of the moment is relatively fast. In opposition to this moment, the conventional helical spring 24 acting through the lever arm 19 provides a counter or opening moment about the pin 18. The bias or force of this spring varies linearly with movement of the spring.

During the early stage of movement of the lid from its closed to theapproximate 45 position of FIG. 3, the reduction in spring force is very substantial and greater in proportion to the reduction of the moment due to the weight of the lid. During the later stage of movement of the lid from the position of FIG. 3 to the position of FIG. 4 assistance is given the expanded spring by varying the angular relation between the tension rod and the arm 19. It will be noted that, during the movement of the lid 11 from the position of FIG. 2 to the position of FIG. 3, the spring remains bent or defiected substantially in an are about its fixed end. The spring position is determined by the position of the fulcrum 29, against which the rod 21 bears, relative the pivot 22 at the end of the rod. During this stage of movement, it will be understood that the compressed spring has sufficient bias to substantially counterbalance the lid.

In the design illustrated,.the aforementioned assistance that is given the spring during the later range of movement of the lid to the full open position (FIG. 4), is initiated when the curved portion 28 of the rod 21 passes over the fulcrum 29. It will be noted that the bias provided by the lateral deflection of the spring tends to swing rod 21 to a vertical position about the fulcrum 29. This biasing force does not become effective in assisting to overcome the closing moment of the lid 10 until the angle between the tension rod 21 and the arm 19 exceeds 90. FIG. 3 illustrates the approximate position of the components of the counterbalancing mechanism as the lateral bias of the spring becomes effective. When the lid occupies positions between those illustrated in FIGS. 3 and 4 its closing moment is, as explained previously, of relatively low magnitude, so that it is readily counterbalanced by the remaining compression bias available from the spring 21 and the additional lateral bias from the spring.

It will be noted from FIG. 4 that when the lid 10 is fully open the spring 21 is nearly fully extended and substantially all of the lateral deflection has been removed from the spring, with the result that only a light counterbalancing force is applied to the lid. This reduction in counterbalancing force to more nearly match the closing moment of the lid as the lid approaches a fully open position is highly desirable in order to prevent the lid from banging to a stop, so to speak, as it is opened.

The fastening devices 30 preferably pass through enlarged openings 33 in the fulcrum plate 29 (see FIG.

to provied a means for adjusting the position of the fulcrum relative the other components of the counterbalancing mechanism. As can be readily appreciated,

shifting the position of the fulcrum 29 changes the amount of lateral deflection imparted to the spring 24 and thereby adjusts the amount of assistance bias which the lateral deflection of the spring affords during the latter range of opening movement of the lid.

A counterbalancing mechanism, constructed substantially as shown, provides for retention of the lid in various angular positions to which it may be moved. This is advantageous during loading or for gaining access to the tub for any reason after a cycle is started.

Dropping and slamming of the lid is prevented. The

mechanism is simple in construction, utilizing an inexpensive coil spring and may be readily assembled and serviced.

While the invention has been shown in but one form,

it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof.

What is claimed is:

1. In a counterbalancing mechanism, the combination with a member movable froma horizontal position to a substantially vertical position, a hinge having a movable portion fixed to the member and a fixed portion, a hinge pin pivotally connecting the fixed and movable portions of the hinge and pivotally supporting said member, an arm extending from said movable portion of the hinge, a helical compression spring having one end anchored adjacent the fixed portion of the hinge and its other end free, a tension rod pivoted to said arm and bearingagainst the free end of the spring for biasing the member toward its vertical position and a fulcrum engaging an intermediate portion of the rod during at least a portion of its travel for ofisetting the free end of the spring and modifying the biasing effect of the spring upon said member.

2. In a counterbalancing mechanism for a cover movable from a horizontal closed position through a first range of movement to a partially open position and thence through a second range of movement to a generally vertical open position, a hinge pivotally supporting the cover, an arm movable with the cover, a tension rod pivoted to the arm and extending therefrom, a helical compression spring having one end thereoffixedly mounted and the other end free-for movements axially of the spring and arcuately about the fixed end of the spring, saidtension rod extending through the spring and supporting the free end thereof and a fulcrum engaging an intermediate portion of the rod and providing for angular movement of the rod relative the arm; the construction and arrangement being such that angularadjustment of the rod relative the arm in the second range of movement of the cover assists the spring in supporting the cover.

3. In a counter-balancing mechanism for a cover movable between a horizontal closed position and a generally vertical open position, a hinge including a pivot movably supporting the cover, an arm fixed to the cover and movable therewith, a tension bar pivoted to said arm, a helical compression spring for biasing the cover toward its open position and having its upper end fixedly positioned and its lower end free for movementaxially of the spring and laterally with respect to the fixed upper end thereof, said tension bar extending through the spring and having its lower end bearing against'th'e lower end of the References Cited in the fileof this patent UNITED STATES PATENTS Dibelka et al Nov. 16 1937 McWethy May 15, 1956 

